Bilateral temporomandibular joint dislocation secondary to acute dystonia induced by antipsychotic depot injection: a case report.

Background: Acute dystonia is a well-recognised extrapyramidal side effect of antipsychotic medications, often presenting within hours to days of administration. While orofacial involvement is common, bilateral temporomandibular joint (TMJ) dislocation as a direct consequence of drug-induced dystonia is exceedingly rare and may be misinterpreted as a primary psychiatric or dental issue. Case Description: A 39-year-old man with schizophrenia had been stable on regular intramuscular flupentixol decanoate (40 mg every four weeks). When his mental health deteriorated, the depot dose was increased. Three weeks later, his sister contacted the general practitioner (GP) about new slurred speech, drooling, and inability to close his mouth. During a home visit, the GP noted facial spasm, trismus, and an open-locked jaw, suggesting bilateral temporomandibular joint (TMJ) dislocation, and arranged urgent referral to the emergency department (ED). In the ED, the patient was distressed and unable to speak or close his mouth. Examination and radiography confirmed bilateral anterior TMJ dislocation. Intravenous diazepam provided little relief, and manual reduction under conscious sedation failed due to severe dystonia. Both joints were successfully reduced under general anaesthesia using the standard two-thumb technique. Symptoms resolved completely, and no recurrence was observed on follow-up. A diagnosis of acute drug-induced dystonia leading to bilateral TMJ dislocation was established, and his antipsychotic regimen was reviewed with the psychiatric team. Conclusions: This case highlights an uncommon mechanical complication of antipsychotic-induced dystonia. Timely recognition and management are essential to avoid airway risk, prolonged joint dysfunction, or misattribution to psychiatric pathology. It reinforces the need for multidisciplinary coordination between emergency medicine, psychiatry, and maxillofacial services.